JP2015115809A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat dissipation structure which efficiently inhibits rising of temperatures of exterior surfaces of an imaging device and an electronic camera without enlarging the electronic camera.SOLUTION: An imaging apparatus includes: an imaging device (20); an imaging circuit board (21) on which the imaging device (20) is mounted; a second heat conduction member (31) attached to the imaging circuit board (21); a main substrate (24) disposed on a rear surface of the imaging circuit board (21); a first heat conduction member (30) which contacts with the second heat conduction member (31) and the main substrate (24); a heat sink (32) in which a part of a shape of a mirror box (7) is formed, the heat sink (32) contacting with the first heat conduction member (30); a fan (33) disposed immediately below the heat sink (32); and a bottom base plate (35) including a tripod screw attachment part (35a) and an exhaust port (35b) located on a top surface.

Description

  The present invention relates to an electronic camera such as a interchangeable lens single-lens reflex digital camera that forms an image of a subject by a photographing lens on an image sensor.

  2. Description of the Related Art Conventionally, an electronic camera equipped with an image sensor such as a CCD receives light transmitted through a photographing lens with an image sensor and obtains image data based on the photoelectric conversion output. Image sensors tend to generate more heat as pixels become larger and larger, but image sensors generate dark current due to heat and cause noise, which reduces image quality. ing. In addition, the amount of heat generated by various electronic circuit elements accompanied by heat generated by the CPU tends to increase as the processing capacity of the image data increases, the processing speed increases, and the other functions and speed of electronic devices increase. There is a problem that the temperature of the entire exterior or local area of the camera rises, resulting in low temperature burns for the photographer, and it is necessary to take heat dissipation measures as soon as possible.

  Various heat dissipation countermeasures have been proposed. For example, Patent Document 1 discloses a proposal in which heat from a heat-generating component is concentrated in a heat dissipation element provided at the lower part of an electronic camera and heat from the heat dissipation element is dissipated to an exterior member. Yes.

  On the other hand, a camera using phase difference detection type automatic focus adjustment (AF) (so-called imaging surface AF) using a phase difference detection pixel provided on a part of an image sensor has been proposed (Patent Document). 2). This eliminates the need for the AF unit that is conventionally disposed under the mirror box.

JP 2008-177917 A JP 2007-47197 A

  However, in the conventional technique disclosed in the above-mentioned Patent Document 1, since the heat dissipating element is arranged on the bottom surface of the camera, a space for the heat dissipating element is required, and thus the size of the device in the height direction is inevitable. . Further, the heat radiation is only described for the image sensor, and it is not said about the heat radiation of various electronic circuit elements accompanied by heat generation represented by the CPU, which may cause a low-temperature burn due to an increase in the exterior surface temperature of the electronic camera.

  Moreover, in the prior art disclosed in Patent Document 2 described above, there is no description about the use of the AF unit space that is no longer necessary, and there is a wasteful space remaining.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a heat dissipation structure that can efficiently suppress an increase in temperature of an exterior surface of an image sensor and an electronic camera without increasing the size of the electronic camera.

  In order to achieve the above object, the present invention provides an imaging device (20), an imaging circuit board (21) on which the imaging device (20) is mounted, and a second attached to the imaging circuit board (21). A heat conductive member (31), a main substrate (24) disposed on the back surface of the imaging circuit board (21), a first heat contact member (31), and a first substrate in contact with the main substrate (24) A heat conduction member (30), a heat sink (32) in contact with the first heat conduction member (30) and having a part of the shape of the mirror box (7), and a position directly below the heat sink (32). A fan (33) and a tripod screw mounting portion (35a) and a bottom base plate (35) having an exhaust port (35b) on the top surface are provided.

  According to the present invention, heat of an electronic circuit element such as an image pickup element and a CPU is concentrated on a heat sink that is disposed directly under the mirror box and forms a part of the mirror box, and is released to the outside through a fan and a tripod mounting screw. Thus, it is possible to provide a heat dissipating structure that can reduce the size of the electronic camera and at the same time efficiently suppress the rise in the temperature of the exterior surface of the imaging device and the electronic camera.

Side surface sectional drawing of the camera concerning embodiment of this invention The heat dissipation block diagram of the camera concerning the embodiment of the present invention The heat dissipation control block diagram of the camera concerning the embodiment of the present invention Flowchart of heat dissipation fan drive control of a camera according to an embodiment of the present invention

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[Example 1]
First, a schematic configuration of the entire camera according to an embodiment of the present invention will be described with reference to FIG.

  FIG. 1 is a side sectional view of a camera according to an embodiment of the present invention.

  Reference numeral 1 denotes a camera body, which includes a front cover 2, a strobe cover 3, a top cover 4, a back cover 5, a bottom cover 6, a mirror box 7, and a frame (not shown). A camera lens (not shown) is detachably attached to the camera body 1 via a mount 10 attached to the mirror box 7. The subject luminous flux captured from the photographic lens is reflected by the quick return mirror 11 and is incident on the focus plate 12 and the pentaprism 13 when observing the subject, and then becomes a photographer observation image via the eyepiece lens system 14. The quick return mirror 11, the focusing plate 12, the pentaprism 13, and the eyepiece lens system 14 form a finder optical system.

  The quick return mirror 11 is a half mirror, and the subject light flux that has passed through the quick return mirror 11 is imaged on the image sensor 20, and the subject image is detected in focus by pressing a release switch (not shown). The The image pickup device 20 includes a phase difference detection pixel provided in a part of the image pickup device, and includes a known phase difference detection type automatic focus adjustment (AF) (so-called image pickup surface AF). Reference numeral 21 denotes an image pickup circuit board on which the image pickup element 20 and an AD conversion element 22 for converting an analog signal from the image pickup element 20 into a digital signal are mounted.

  23 is a known low-pass filter. Reference numeral 24 denotes a main board on which a CPU 25 for controlling the operation of the camera is mounted. Reference numeral 8 denotes a receiving dowel for locking the main board 24 and the first heat conducting member 30 and the second heat conducting member 31 described in detail later. The dowel 8 is formed integrally with a frame (not shown). Reference numeral 9 denotes an external display for displaying a subject image captured by the image sensor 20. 32 is a heat sink attached to the mirror box 7, and the detailed shape will be described later.

  Reference numeral 33 denotes a fan for releasing the heat of the heat sink to the outside, and is attached to the bottom substrate 34. Reference numeral 35 denotes a bottom base plate having a tripod screw mounting portion 35a in which a tripod screw is cut and an exhaust port 35b for releasing heat. A drip-proof sheet 36 made of a waterproof and moisture-permeable material is attached to the upper portion of the exhaust port 35 b of the bottom base plate 35. The bottom surface of the tripod screw mounting portion 35a is recessed from the exterior surface of the bottom cover 6 so that the user cannot directly touch it. A thermometer 37 measures the temperature of the internal space 7a of the mirror box 7.

  Next, a heat dissipation configuration of the camera according to the embodiment of the present invention will be described with reference to FIG. When shooting is started, a subject image is captured by the image sensor 20, and the image sensor 20 sends an analog image signal to the AD conversion element 22 mounted on the image pickup circuit board 21. After being converted into a digital signal by the AD conversion element 22, it is sent to the CPU 25 mounted on the main board 24 for image processing.

  By performing these operations, the imaging element 20, the imaging circuit board 21, the AD conversion element 22, the main board 24, and the CPU 25 generate heat. One end of the second heat conducting member 31 made of graphite sheet or the like is pasted on the AD converting element 22 for the heat of the image pickup device 20, the image pickup circuit board 21, and the AD conversion device 22, and the other end of the second heat conducting member 31 is attached. Is transferred to the first heat conducting member 30 made of a plate material such as a copper plate or aluminum. Further, the heat of the main board 24 and the CPU 25 is received by the screw 38 and fixed to the dowel 8 by screwing, so that the copper foil exposed portion 24a provided on the main board 24 directly contacts the first heat conducting member 30 and is transmitted. Be heated.

  The first heat conducting member 30 is fixed to a flange 32a formed on the heat sink 32 with a screw (not shown), whereby the heat resistance of the first heat conducting member 30 is reduced as much as possible and heat transfer is efficiently performed. The The heat received from the first heat conducting member 30 is formed in the heat sink 32 from the light shielding line surface 32b where the light shielding lines are cut and the slit portion 32c where the slits are cut, respectively, and the internal space 7a and the bottom base rate of the mirror box 7 respectively. Radiated to the 35 side. The shading line surface 32b is painted because it has an external appearance, but a heat-absorbing coating material may be applied to suppress the heat generated in the internal space 7a. While the heat radiated to the bottom base rate 35 side remains in the space, it is discharged to the outside through the exhaust port 35b provided at the top of the tripod screw mounting portion 35a. In order to prevent water droplets from entering the camera, the above-described drip-proof sheet 36 is attached to the exhaust port 35b.

  On the other hand, when the temperature of the internal space 7a of the mirror box 7 rises, the photographing optical axis is distorted by heat, so that there is a problem that the optical path length is extended and the pin is displaced. Therefore, the temperature of the internal space 7a of the mirror box 7 is monitored by the thermometer 37. When the temperature reaches a predetermined temperature, the fan 33 is driven, and the heat generated in the internal space 7a of the mirror box 7 is discharged to the discharge hole 32d provided in the heat sink 32d. To the bottom base rate 35 side. In the heat sink 32, the light shielding lines and the slits are cut in the same direction, so that the heat sink 32 can be molded with an extruded material.

  Next, a heat dissipation control block of the camera according to the embodiment of the present invention will be described with reference to FIG.

  Reference numeral 101 denotes a cooling mode discriminating unit that discriminates an input state of a cooling mode switch provided in a camera (not shown). Reference numeral 102 denotes a temperature detection circuit that performs monitor management of the thermometer 37. Reference numeral 103 denotes a cooling device drive circuit that controls driving of the fan 33 in accordance with a command from the CPU 25. A tripod screw attachment detection unit 104 detects whether an external accessory or a tripod tripod screw is engaged with the tripod screw attachment portion 35a using a detection switch (not shown), and transmits information to the CPU 25. In response to this, the CPU 25 controls the driving of the fan 33.

  Next, drive control of the heat radiating fan of the camera according to the embodiment of the present invention will be described with reference to the flowchart of FIG.

  This flow starts when the main power of the camera is turned on and is executed by the CPU 25. In step S201, it is determined whether or not the cooling mode is on. This is determined based on the output of the cooling mode determining means 101 to the CPU 25 described above. The process proceeds to step S202 only when the cooling mode is on. In step S202, the tripod screw attachment detection means 104 determines whether an external accessory or a tripod tripod screw is attached to the tripod screw attachment portion 35a. When it is determined that the tripod screw is not attached, the process proceeds to step S204 to start photographing. If it is determined that the tripod screw is attached, the process proceeds to step S203, and after the fan energy saving drive mode is set, the process proceeds to step S204.

  In this case, when an external accessory or a tripod screw of a tripod is attached to the tripod screw part attachment portion 35a, the heat escapes to the external accessory or the tripod side via the tripod screw, so that cooling by the fan 33 is not necessary. Because. When shooting is started in step S203, the process proceeds to step S205, and monitoring of the temperature of the internal space 7a of the mirror box 7 is started by the thermometer 37 arranged in the mirror box 7. When the temperature of the internal space 7a of the mirror box 7 reaches a predetermined value or more, the CPU 25 sends a signal to the cooling drive circuit 103 and proceeds to step S206 to drive the fan.

  In step S207, the temperature in the mirror box 7 is continuously monitored even during fan driving. Here, when the temperature of the internal space 7a of the mirror box 7 becomes equal to or lower than the predetermined temperature, the process proceeds to step S208, the fan is stopped, and it waits until the temperature of the internal space 7a of the mirror box 7 reaches the predetermined temperature.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

7 mirror box 7a internal space 20 image pickup device 21 image pickup circuit board 24 main board 30 first heat conducting member 31 second heat conducting member 32 heat sink 33 fan 35 bottom base plate 35a tripod screw attaching portion 35b exhaust port

Claims (4)

  The imaging element (20), the imaging circuit board (21) on which the imaging element (20) is mounted, the second heat conducting member (31) attached to the imaging circuit board (21), and the imaging circuit board A main board (24) disposed on the back surface of (21), the second heat conduction member (31), the first heat conduction member (30) in contact with the main board (24), and the first A heat sink (32) in contact with the heat conducting member (30) and a part of the shape of the mirror box (7), a fan (33) disposed immediately below the heat sink (32), and a tripod screw mounting portion An imaging apparatus comprising: (35a) and a bottom base plate (35) having an exhaust port (35b) on the top surface.   The thermometer (37) is provided in the mirror box (7), and the fan (33) is driven when the thermometer (37) reaches a predetermined temperature. Shooting device.   The photographing device according to claim 1, wherein when the tripod screw is attached to the tripod screw attachment portion (35a), the fan (33) is stopped or the driving speed is reduced.   The photographing apparatus according to claim 1, wherein the heat sink (32) has a discharge hole (32d) penetrating between the internal space (7a) of the mirror box (7) and the fan (33).